JP2011256472A - Polylactic acid containing composite fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid containing composite fiber in which the hydrolysis resistance is enhanced and odors due to a free isocyanate compound are not generated at the time of operation and melting.SOLUTION: Provided is a polylactic acid containing composite fiber including a polylactic acid composition that contains polylactic acid and a compound (component C) including a carbodiimide group-having cyclic structure in which a first nitrogen and a second nitrogen are combined by a coupling group.

Description

  The present invention relates to a polylactic acid-containing composite fiber having practical heat resistance and durability, and particularly improved hydrolysis resistance.

  In recent years, with increasing awareness of the environment on a global scale, polylactic acid synthesized from raw materials derived from plant-derived components has attracted attention. Polylactic acid is a polymer made from lactic acid obtained by fermenting starch or cellulose extracted from plants. Among plant-derived polymers, the balance of mechanical properties, heat resistance, and cost is excellent. Development of resin products, fibers, films, sheets, and the like using this has been performed.

  Among these, polylactic acid fibers are being developed for use in clothing, curtains, carpets, interiors, vehicle interiors, and industrial materials. Plant-derived polylactic acid resins and other polymers In addition, the development of environmentally friendly composite fibers with a high ratio of plant raw materials is also progressing. However, since polylactic acid fibers are susceptible to hydrolysis, there is a problem that the product life is short, and when this fiber is used as a composite fiber, its application development is limited.

In order to solve this problem, Patent Documents 1 and 2 propose polylactic acid in which hydrolysis resistance is improved by adding a carbodiimide compound or the like. However, when the carbodiimide compound used is used as an end-capping agent for a polymer compound, the compound having an isocyanate group is liberated as the carbodiimide compound binds to the end of polylactic acid, generating a unique odor of the isocyanate compound. However, deteriorating the working environment has been a problem.
In Patent Document 3, an attempt is made to improve hydrolysis resistance with a glycidyl-modified compound, but the carbodiimide compound is still more excellent in end-capping performance.

JP 2009-256837 A JP 2009-256838 A JP 2008-031623 A

  The object of the present invention is to provide a polylactic acid-containing composite fiber that solves the above-mentioned problems of the prior art, has improved hydrolysis resistance, and does not generate a free isocyanate compound when melted. is there.

  As a result of intensive investigations on improvement of wear resistance and hydrolysis resistance of polylactic acid-containing composite fiber fibers and further improvement of working environment, the present inventors have found that polylactic acid has a polymer chain end of polylactic acid polymer and Even if it reacted, if it was a composition containing the carbodiimide compound which has a specific structure which does not liberate an isocyanate compound, it discovered that the said objective was achieved and completed this invention.

That is, the object of the present invention is to
A polylactic acid-containing composite fiber comprising a polylactic acid composition containing a polylactic acid and a compound (C component) containing a cyclic structure in which one carbodiimide group and the first nitrogen and the second nitrogen are bonded by a bonding group Achieved by:

According to the present invention, a polylactic acid-containing composite fiber having improved hydrolysis resistance can be provided.
Furthermore, the terminal of polylactic acid can be sealed with a carbodiimide compound without releasing the isocyanate compound. As a result, the generation of malodor due to the free isocyanate compound can be suppressed, and the working environment can be improved.

  Moreover, when the end of polylactic acid is sealed with a cyclic carbodiimide compound, an isocyanate group is formed at the end of polylactic acid, and the reaction of the isocyanate group makes it possible to increase the molecular weight of polylactic acid. The cyclic carbodiimide compound also has an action of capturing a free monomer in polylactic acid and other compounds having an acidic group. Furthermore, according to the present invention, the cyclic carbodiimide compound has an advantage that it can be end-capped under milder conditions as compared with a linear carbodiimide compound that is usually used by having a cyclic structure.

The difference between the linear carbodiimide compound and the cyclic carbodiimide compound in the end-capping reaction mechanism is as described below.
When a linear carbodiimide compound (R ₁ —N═C═N—R ₂ ) is used as a carboxyl terminal blocking agent for polylactic acid, the reaction is represented by the following formula. When the linear carbodiimide compound reacts with a carboxyl group, an amide group is formed at the terminal of polylactic acid, and an isocyanate compound (R ₁ NCO) is released.

（式中、Ｗはポリ乳酸の主鎖である。）

(Wherein, W is the main chain of polylactic acid.)

  On the other hand, when a cyclic carbodiimide compound is used as a carboxyl terminal blocking agent for polylactic acid, the reaction is represented by the following formula. It can be seen that when the cyclic carbodiimide compound reacts with a carboxyl group, an isocyanate group (-NCO) is formed at the terminal of polylactic acid via an amide group, and the isocyanate compound is not liberated.

（式中、Ｗはポリ乳酸の主鎖であり、Ｑは、脂肪族基、脂環族基、芳香族基またはこれらの組み合わせである２〜４価の結合基である。）

(Wherein, W is the main chain of polylactic acid, and Q is an aliphatic group, alicyclic group, aromatic group, or a divalent to tetravalent linking group that is a combination thereof.)

<Cyclic carbodiimide compound (component C)>
In the present invention, the cyclic carbodiimide compound (C component) has a cyclic structure. The cyclic carbodiimide compound may have a plurality of cyclic structures.
The cyclic structure has one carbodiimide group (—N═C═N—), and the first nitrogen and the second nitrogen are bonded by a bonding group. One cyclic structure has only one carbodiimide group. For example, when there are a plurality of cyclic structures in the molecule, such as a spiro ring, one cyclic structure bonded to a spiro atom is included in each cyclic structure. Needless to say, the compound may have a plurality of carbodiimide groups as long as it has a carbodiimide group. The number of atoms in the cyclic structure is preferably 8 to 50, more preferably 10 to 30, further preferably 10 to 20, and particularly preferably 10 to 15.

  Here, the number of atoms in the ring structure means the number of atoms that directly constitute the ring structure, and is, for example, 8 for an 8-membered ring and 50 for a 50-membered ring. This is because if the number of atoms in the cyclic structure is smaller than 8, the stability of the cyclic carbodiimide compound is lowered, and it may be difficult to store and use. From the viewpoint of reactivity, there is no particular restriction on the upper limit of the number of ring members, but cyclic carbodiimide compounds having more than 50 atoms are difficult to synthesize, and the cost may increase significantly. From this viewpoint, the number of atoms in the cyclic structure is preferably 10-30, more preferably 10-20, and particularly preferably 10-15.

The cyclic structure is preferably a structure represented by the following formula (1).

  In the formula, Q is a divalent to tetravalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, each of which may contain a hetero atom and a substituent. A heteroatom in this case refers to O, N, S, P. Two of the valences of this linking group are used to form a cyclic structure. When Q is a trivalent or tetravalent linking group, it is bonded to a polymer or other cyclic structure via a single bond, a double bond, an atom, or an atomic group.

The linking group may include a heteroatom and a substituent, each having a divalent to tetravalent carbon number of 1 to 20 aliphatic group, a divalent to tetravalent carbon number of 3 to 20 alicyclic group, A linking group which is a tetravalent aromatic group having 5 to 15 carbon atoms or a combination thereof and has a necessary number of carbon atoms to form the cyclic structure defined above is selected. Examples of combinations include structures such as an alkylene-arylene group in which an alkylene group and an arylene group are bonded.
The linking group (Q) is preferably a divalent to tetravalent linking group represented by the following formula (1-1), (1-2) or (1-3).

In the formula, Ar ¹ and Ar ² are each independently a 2- to 4-valent aromatic group having 5 to 15 carbon atoms which may contain a hetero atom and a substituent.
As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group (divalent) include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

R ¹ and R ² each independently contain a heteroatom and a substituent, each having 2 to 4 valent aliphatic groups having 1 to 20 carbon atoms and 2 to 4 valent fatty acids having 3 to 20 carbon atoms A cyclic group, and a combination thereof, or a combination of the aliphatic group, the alicyclic group, and a divalent to tetravalent aromatic group having 5 to 15 carbon atoms.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As cycloalkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group Group, cyclododecane triyl group, cyclohexadecane triyl group and the like. As cycloalkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Yl group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

X ¹ and X ² each independently contain a heteroatom and a substituent, each having a 2 to 4 valent aliphatic group having 1 to 20 carbon atoms and a 2 to 4 valent fatty acid having 3 to 20 carbon atoms It is a cyclic group, a divalent to tetravalent aromatic group having 5 to 15 carbon atoms, or a combination thereof.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As the alkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group , Cyclododecanetriyl group, cyclohexadecanetriyl group and the like. As the alkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

In the formulas (1-1) and (1-2), s and k are integers of 0 to 10, preferably 0 to 3, more preferably 0 to 1. When s and k exceed 10, the cyclic carbodiimide compound is difficult to synthesize, and the cost may increase significantly. From this viewpoint, the integer is preferably selected in the range of 0 to 3. When s or k is 2 or more, X ¹ or X ² as a repeating unit may be different from other X ¹ or X ² .

X ³ is a divalent to tetravalent C 1-20 aliphatic group, a divalent to tetravalent C 3-20 alicyclic group, each of which may contain a heteroatom and a substituent, A tetravalent aromatic group having 5 to 15 carbon atoms, or a combination thereof.

  Examples of the aliphatic group include an alkylene group having 1 to 20 carbon atoms, an alkanetriyl group having 1 to 20 carbon atoms, and an alkanetetrayl group having 1 to 20 carbon atoms. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, a dodecylene group, and a hexadecylene group. As the alkanetriyl group, methanetriyl group, ethanetriyl group, propanetriyl group, butanetriyl group, pentanetriyl group, hexanetriyl group, heptanetriyl group, octanetriyl group, nonanetriyl group, decantriyl group, dodecantriyl group, Examples include a hexadecantriyl group. As alkanetetrayl group, methanetetrayl group, ethanetetrayl group, propanetetrayl group, butanetetrayl group, pentanetetrayl group, hexanetetrayl group, heptanetetrayl group, octanetetrayl group, nonanetetrayl group Decanetetrayl group, dodecanetetrayl group, hexadecanetetrayl group and the like. These aliphatic groups may contain a substituent, such as an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, or an ester group. , Ether group, aldehyde group and the like.

  Examples of the alicyclic group include a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkanetriyl group having 3 to 20 carbon atoms, and a cycloalkanetetrayl group having 3 to 20 carbon atoms. Examples of the cycloalkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cycloheptylene group, a cyclooctylene group, a cyclononylene group, a cyclodecylene group, a cyclododecylene group, and a cyclohexadecylene group. As the alkanetriyl group, cyclopropanetriyl group, cyclobutanetriyl group, cyclopentanetriyl group, cyclohexanetriyl group, cycloheptanetriyl group, cyclooctanetriyl group, cyclononanetriyl group, cyclodecanetriyl group , Cyclododecanetriyl group, cyclohexadecanetriyl group and the like. As the alkanetetrayl group, cyclopropanetetrayl group, cyclobutanetetrayl group, cyclopentanetetrayl group, cyclohexanetetrayl group, cycloheptanetetrayl group, cyclooctanetetrayl group, cyclononanetetrayl group, cyclodecanetetrayl group Group, cyclododecanetetrayl group, cyclohexadecanetetrayl group and the like. These alicyclic groups may contain a substituent, such as an alkyl group having 1 to 20 carbon atoms, an arylene group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, and an ester. Group, ether group, aldehyde group and the like.

  As an aromatic group, each of which contains a hetero atom and may have a heterocyclic structure, an arylene group having 5 to 15 carbon atoms, an arenetriyl group having 5 to 15 carbon atoms, an arenetetra having 5 to 15 carbon atoms Yl group. Examples of the arylene group include a phenylene group and a naphthalenediyl group. Examples of the arenetriyl group (trivalent) include a benzenetriyl group and a naphthalenetriyl group. Examples of the arenetetrayl group (tetravalent) include a benzenetetrayl group and a naphthalenetetrayl group. These aromatic groups may be substituted. Examples of the substituent include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 15 carbon atoms, a halogen atom, a nitro group, an amide group, a hydroxyl group, an ester group, an ether group, and an aldehyde group.

Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ may contain a hetero atom, and when Q is a divalent linking group, Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ are all divalent groups. When Q is a trivalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ is a trivalent group. When Q is a tetravalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ is a tetravalent group or two are trivalent It is a group.

  Examples of the cyclic carbodiimide compound used in the present invention include compounds represented by the following formulas (2) to (4).

<Cyclic carbodiimide compound (2)>

  In the formula, Qa is a divalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a heteroatom. The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (2), the aliphatic group, alicyclic group, and aromatic group are all divalent. Qa is preferably a divalent linking group represented by the following formula (2-1), (2-2) or (2-3).

In the formula, Ar _a ¹ , Ar _a ² , R _a ¹ , R _a ² , X _a ¹ , X _a ² , X _a ³ , s and k are represented by formulas (1-1) to (1-3), respectively. Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k. However, these are all divalent.
Examples of the cyclic carbodiimide compound (2) include the following compounds.

<Cyclic carbodiimide compound (3)>

Wherein, Q _b is an aliphatic group, an alicyclic group, an aromatic group or a trivalent linking group combinations thereof, and may contain a hetero atom. Y is a carrier supporting a cyclic structure. The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (3), one of the groups constituting Qb is trivalent. Q _b is preferably a trivalent linking group represented by the following formula (3-1), (3-2) or (3-3).

In the formula, Ar _b ¹ , Ar _b ² , R _b ¹ , R _b ² , X _b ¹ , X _b ² , X _b ³ , s and k are respectively represented by the formulas (1-1) to (1-3). The same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k. However, one of these is a trivalent group.
Y is preferably a single bond, a double bond, an atom, an atomic group or a polymer. Y is a bonding portion, and a plurality of cyclic structures are bonded via Y to form a structure represented by the formula (3). Examples of the cyclic carbodiimide compound (3) include the following compounds.

<Cyclic carbodiimide compound (4)>

In the formula, Q _c is a tetravalent linking group which is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may have a hetero atom. Z ¹ and Z ² are carriers that support a cyclic structure. Z ¹ and Z ² may be bonded to each other to form a cyclic structure.
The aliphatic group, alicyclic group, and aromatic group are the same as those described in Formula (1). However, in the compound of formula (4), Q _c is tetravalent. Accordingly, one of these groups is a tetravalent group or two are trivalent groups. Q _c is preferably a tetravalent linking group represented by the following formula (4-1), (4-2) or (4-3).

Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² , X _c ³ , s and k are each Ar ^{1 in} formulas (1-1) to (1-3). , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k are the same. Provided that Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² and X _c ³ are one of which is a tetravalent group or two of which are trivalent It is a group.
Z ¹ and Z ² are preferably each independently a single bond, a double bond, an atom, an atomic group or a polymer. Z ¹ and Z ² are bonding portions, and a plurality of cyclic structures are bonded via Z ¹ and Z ² to form a structure represented by the formula (4).
Examples of the cyclic carbodiimide compound (4) include the following compounds.

<Method for producing cyclic carbodiimide compound>
The cyclic carbodiimide compound can be produced by a conventionally known method. For example, a method for producing an amine body via an isocyanate body, a method for producing an amine body via an isothiocyanate body, a method for producing an amine body via a triphenylphosphine body, a urea body from an amine body The method of manufacturing via a thiourea body, the method of manufacturing via a thiourea body, the method of manufacturing from a carboxylic acid body via an isocyanate body, the method of manufacturing a lactam body, etc. are mentioned.

  Moreover, the cyclic carbodiimide compound of this invention can be manufactured combining and changing the method described in the following literatures, and an appropriate method can be employ | adopted according to the compound to manufacture.

Tetrahedron Letters, Vol. 34, no. 32, 515-5158, 1993.
Medium- and Large-Membered Rings from Bis (iminophosphoranes): An Efficient Preparation of Cyclic Carbidiimides, Pedro Molina et al.
Journal of Organic Chemistry, Vol. 61, no. 13, 4289-4299, 1996.
New Models for the Study of the Racemization Mechanism of Carbodiimides. Synthesis and Structure (X-ray Crystallography and 1H NMR) of Cyclic Carbodiimides, Pedro Molina et al.
Journal of Organic Chemistry, Vol. 43, No8, 1944-1946, 1978.
Macrocyclic Ureas As Masked Isocynates, Henri Ulrich et al.
Journal of Organic Chemistry, Vol. 48, no. 10, 1694-1700, 1983.
Synthesis and Reactions of Cyclic Carbodiimides,
R. Richter et al.
Journal of Organic Chemistry, Vol. 59, no. 24, 7306-7315, 1994.
A New and Efficient Preparation of Cyclic Carbodiamids from Bis (iminophosphoranea) and the System Boc ₂ O / DMAP, Pedro Molina et al.

（２）得られたニトロ体を還元して下記式（ｄ）で表わされるアミン体を得る工程、

（３）得られたアミン体とトリフェニルホスフィンジブロミドを反応させ下記式（ｅ）で表されるトリフェニルホスフィン体を得る工程、および

（４）得られたトリフェニルホスフィン体を反応系中でイソシアネート化した後、直接脱炭酸させることによって製造したものは、本願発明に用いる環状カルボジイミド化合物として好適に用いることができる。
（上記式中、Ａｒ^１およびＡｒ^２は各々独立に、炭素数１〜６のアルキル基またはフェニル基で置換されていてもよい芳香族基である。Ｅ^１およびＥ^２は各々独立に、ハロゲン原子、トルエンスルホニルオキシ基およびメタンスルホニルオキシ基、ベンゼンスルホニルオキシ基、ｐ−ブロモベンゼンスルホニルオキシ基からなる群から選ばれる基である。Ａｒ^ａは、フェニル基である。Ｘは、下記式（ｉ−１）から（ｉ−３）の結合基である。） Depending on the compound to be produced, an appropriate production method may be employed. For example, (1) nitrophenol represented by the following formula (a-1), nitrophenol represented by the following formula (a-2), and A step of reacting a compound represented by the following formula (b) to obtain a nitro compound represented by the following formula (c);

(2) A step of reducing the obtained nitro body to obtain an amine body represented by the following formula (d);

(3) a step of reacting the obtained amine body with triphenylphosphine dibromide to obtain a triphenylphosphine body represented by the following formula (e); and

(4) After the obtained triphenylphosphine body is isocyanated in the reaction system and then directly decarboxylated, it can be suitably used as the cyclic carbodiimide compound used in the present invention.
(In the above formula, Ar ¹ and Ar ² are each independently an aromatic group optionally substituted with an alkyl group having 1 to 6 carbon atoms or a phenyl group. E ¹ and E ² are each independently a halogen atom. A group selected from the group consisting of an atom, a toluenesulfonyloxy group, a methanesulfonyloxy group, a benzenesulfonyloxy group, and a p-bromobenzenesulfonyloxy group, Ar ^a is a phenyl group, X is represented by the following formula (i -1) to (i-3).

（式中、ｎは１〜６の整数である。）

(In the formula, n is an integer of 1 to 6.)

（式中、ｍおよびｎは各々独立に０〜３の整数である。）

(In the formula, m and n are each independently an integer of 0 to 3.)

（式中、Ｒ^１およびＲ^２は各々独立に、炭素数１〜６のアルキル基、フェニル基を表す。）

(In the formula, R ¹ and R ² each independently represents an alkyl group having 1 to 6 carbon atoms or a phenyl group.)

<Polylactic acid>
In the polylactic acid of the present invention, the main chain is mainly composed of lactic acid units represented by the following formula (I), and at least a part of the ends are sealed with a cyclic carbodiimide compound. In the present invention, “mainly” is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and still more preferably 98 to 100 mol%.

  The lactic acid unit represented by the formula (I) includes an L-lactic acid unit and a D-lactic acid unit which are optical isomers. The main chain of polylactic acid may be mainly L-lactic acid units, D-lactic acid units, or a combination thereof.

From the viewpoint of improving heat resistance, polylactic acid is composed of poly-D-lactic acid whose main chain is mainly composed of D-lactic acid units and poly-L-lactic acid whose main chain is mainly composed of L-lactic acid units. Particularly preferred is a stereocomplex polylactic acid.
Here, the proportion of other units constituting the main chain is preferably in the range of 0 to 10 mol%, more preferably 0 to 5 mol%, and still more preferably 0 to 2 mol%.

Stereocomplex crystals usually have a higher melting point than crystals formed solely by poly-L-lactic acid or poly-D-lactic acid, so that even if they are contained in a small amount, the effect of increasing heat resistance can be expected. This is noticeable when the amount of stereocomplex crystals is large. The stereocomplex crystallinity (S) according to the following formula is preferably 95% or more, and more preferably 100%.
S = [ΔHms / (ΔHmh + ΔHms)] × 100
(However, ΔHms is the melting enthalpy of stereocomplex phase crystals, and ΔHmh is the melting enthalpy of homophase polylactic acid crystals.)

In order to stably and highly advance the formation of stereocomplex polylactic acid crystals, a method of blending specific additives is preferably applied.
For example, a technique of adding a metal phosphate represented by the following formula as a stereocomplex crystallization accelerator can be mentioned.

In the formula, R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ¹² and R ¹³ each independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M ₁ represents Represents an alkali metal atom, an alkaline earth metal atom, a zinc atom or an aluminum atom, p represents 1 or 2, q represents 0 when M ₁ is an alkali metal atom, an alkaline earth metal atom or a zinc atom; When it is an atom, it represents 1 or 2.

In the formula, each of R ¹⁴ , R ¹⁵ and R ¹⁶ independently represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and M ₂ represents an alkali metal atom, an alkaline earth metal atom, a zinc atom or an aluminum atom. P represents 1 or 2, q represents 0 when M ₂ is an alkali metal atom, alkaline earth metal atom or zinc atom, and 1 or 2 when M ₂ is an aluminum atom.

M ₁ and M ₂ of the metal phosphate represented by the above two formulas are preferably Na, K, Al, Mg, Ca and Li, and in particular, Li, Al is the most among K, Na, Al and Li. It can be used suitably.
As these metal phosphates, trade names manufactured by ADEKA Corporation, “ADEKA STAB” NA-11, NA-71 and the like are exemplified as suitable agents.

The metal phosphate is used in an amount of 0.001 to 2 wt%, preferably 0.005 to 1 wt%, more preferably 0.01 to 0.5 wt%, more preferably 0.02 to 0.3 wt% with respect to polylactic acid. It is preferable. If the amount is too small, the effect of improving the stereocomplex crystallinity (S) is small. If the amount is too large, the stereocomplex crystal melting point is lowered. Furthermore, in order to reinforce the action of the metal phosphate, a known crystallization nucleating agent can be used in combination. Of these, calcium silicate, talc, kaolinite, and montmorillonite are preferably selected.
The amount of crystallization nucleating agent used is selected in the range of 0.05 to 5 wt%, more preferably 0.06 to 2 wt%, and still more preferably 0.06 to 1 wt% with respect to polylactic acid.

  Polylactic acid may be obtained by any manufacturing method. For example, a polylactic acid production method includes a two-stage lactide method in which L-lactic acid and / or D-lactic acid is used as a raw material to generate lactide, which is a cyclic dimer, and then ring-opening polymerization is performed. It can be suitably obtained by a generally known polymerization method such as a one-step direct polymerization method in which dehydration condensation is directly performed in a solvent using lactic acid and / or D-lactic acid as a raw material.

  Polylactic acid may contain a carboxylic acid group in its production, but the smaller the amount of the carboxylic acid group contained, the better. For these reasons, it is preferable to use, for example, ring-opened polymerization from lactide using an initiator other than water, or a polymer that has been chemically treated after polymerization to reduce carboxylic acid groups.

  The weight average molecular weight of polylactic acid is usually at least 50,000, preferably at least 100,000, preferably 100,000 to 300,000. When the average molecular weight is lower than 50,000, the strength properties of the fiber are lowered, which is not preferable. If it exceeds 300,000, the melt viscosity becomes too high, and melt spinning may be difficult.

  The polylactic acid in the present invention may be a copolymerized polylactic acid obtained by copolymerizing other components having ester forming ability in addition to L-lactic acid and D-lactic acid. The copolymerizable component includes glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, hydroxycarboxylic acids such as 6-hydroxycaproic acid, ethylene glycol, propylene glycol, butanediol, neo Compounds containing a plurality of hydroxyl groups in the molecule such as pentyl glycol, polyethylene glycol, glycerin and pentaerythritol or derivatives thereof, compounds containing a plurality of carboxylic acid groups in the molecule such as adipic acid, sebacic acid and fumaric acid Or derivatives thereof. However, in order to maintain a high melting point and not impair fiber strength, in this case, it is desirable that 70 mol% or more of the polymer is composed of lactic acid units.

  The polylactic acid composition of the present invention contains end-capped polylactic acid having a structure in which a cyclic carbodiimide compound is bonded to the end of polylactic acid. The cyclic carbodiimide compound reacts with the carboxyl group of polylactic acid as follows to form the following structure at the end of polylactic acid.

（式中、Ｗはポリ乳酸の主鎖で、Ｑは、脂肪族基、脂環族基、芳香族基またはこれらの組み合わせである２〜４価の結合基である。）

(Wherein, W is the main chain of polylactic acid, and Q is an aliphatic group, alicyclic group, aromatic group, or a divalent to tetravalent linking group that is a combination thereof.)

  As will be described later, the polylactic acid-containing composite fiber of the present invention can be produced by melt composite spinning of a polylactic acid composition obtained by mixing polylactic acid and cyclic carbodiimide with different components. The cyclic carbodiimide compound reacts with the end of polylactic acid to seal the end, but when an excess cyclic carbodiimide compound is present, it remains unreacted in the polylactic acid composition. At this time, the polylactic acid-containing composite fiber contains polylactic acid with a sealed end and a cyclic carbodiimide compound, but may also contain polylactic acid with an unsealed end depending on the degree of terminal modification reaction. is there.

In the polylactic acid composition constituting the composite fiber, the content of the cyclic carbodiimide compound remaining in the composition in an unreacted state is 0.001 to 10 parts by weight, preferably 0, per 100 parts by weight of polylactic acid. 0.01 to 5 parts by weight, more preferably 0.1 to 1 part by weight.
If there is a cyclic carbodiimide compound remaining in the composition in an unreacted state, the hydrolysis resistance can be further improved.

  The addition of the cyclic carbodiimide compound to the polylactic acid can be performed at any stage from immediately after the completion of the polymerization reaction of the polylactic acid until it is discharged from the spinneret. For example, the cyclic carbodiimide compound is added to the polylactic acid chip as a powder. Examples thereof include a method of adding, and a method of forcibly melt-kneading polylactic acid and a cyclic carbodiimide compound at a stage before melt spinning.

  The method for adding and mixing the cyclic carbodiimide compound to the polylactic acid is not particularly limited, and a method of adding a solution, a melt or a master batch of polylactic acid to be applied by a conventionally known method, or a cyclic carbodiimide compound is dissolved, dispersed or melted. For example, a method can be used in which a solid of polylactic acid is brought into contact with the liquid being infiltrated and the cyclic carbodiimide compound is permeated.

  When taking the method of adding as a solution, a melt or a master batch of polylactic acid to be applied, it can be added using a conventionally known kneading apparatus. In kneading, a kneading method in a solution state or a kneading method in a molten state is preferable from the viewpoint of uniform kneading properties. The kneading apparatus is not particularly limited, and examples thereof include conventionally known vertical reaction vessels, mixing tanks, kneading tanks or uniaxial or multiaxial horizontal kneading apparatuses such as uniaxial or multiaxial ruders and kneaders. The kneading time is not particularly specified and depends on the kneading apparatus and the kneading temperature, but is selected from 0.1 minutes to 2 hours, preferably from 0.2 minutes to 1 hour, more preferably from 1 minute to 30 minutes.

As a solvent, what is inactive with respect to polylactic acid and a cyclic carbodiimide compound can be used. In particular, a solvent is preferred to have affinity for both and at least partially dissolve both, or at least partially dissolve in both.
As such a solvent, for example, a hydrocarbon solvent, a ketone solvent, an ester solvent, an ether solvent, a halogen solvent, an amide solvent and the like can be used.

Examples of the hydrocarbon solvent include hexane, cyclohexane, benzene, toluene, xylene, heptane, decane and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, cyclohexanone, and isophorone. Examples of ester solvents include ethyl acetate, methyl acetate, ethyl succinate, methyl carbonate, ethyl benzoate, and diethylene glycol diacetate. Examples of the ether solvent include diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, triethylene glycol diethyl ether, diphenyl ether and the like. Examples of the halogen solvent include dichloromethane, chloroform, tetrachloromethane, dichloroethane, 1,1 ′, 2,2′-tetrachloroethane, chlorobenzene, dichlorobenzene and the like. Examples of amide solvents include formamide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone and the like.
These solvents may be used alone or as a mixed solvent as desired.

  In the present invention, the solvent is applied in the range of 1 to 1,000 parts by weight per 100 parts by weight of the total of polylactic acid and the cyclic carbodiimide compound. If the amount is less than 1 part by weight, there is no significance in applying the solvent. The upper limit of the amount of solvent used is not particularly limited, but is about 1,000 parts by weight from the viewpoints of operability and reaction efficiency.

  When a method in which a polylactic acid solid is brought into contact with a liquid in which the cyclic carbodiimide compound is dissolved, dispersed or melted and the cyclic carbodiimide compound is infiltrated, the solid polylactic acid is brought into contact with the carbodiimide dissolved in the solvent as described above. And a method of bringing solid polylactic acid into contact with an emulsion solution of carbodiimide. As a method of contacting, a method of immersing polylactic acid, a method of applying to polylactic acid, a method of spraying, and the like can be suitably used.

  The sealing reaction with the cyclic carbodiimide compound is possible at a temperature of room temperature (25 ° C.) to about 300 ° C., but is more accelerated in the range of 50 to 250 ° C., more preferably 80 to 200 ° C. from the viewpoint of reaction efficiency. . The reaction of polylactic acid is more likely to proceed in a molten state, but the reaction is preferably performed at a temperature lower than 300 ° C. in order to suppress volatilization and decomposition of the cyclic carbodiimide compound. It is also effective to apply a solvent to lower the melting temperature of polylactic acid and increase the stirring efficiency.

  Although the reaction proceeds sufficiently rapidly without a catalyst, a catalyst that accelerates the reaction can also be used. As a catalyst, the catalyst used with the conventional linear carbodiimide compound is applicable. These can be used alone or in combination of two or more. The addition amount of the catalyst is not particularly limited, but is preferably 0.001 to 1 part by weight, and 0.01 to 0.1 part by weight with respect to 100 parts by weight of the total of polylactic acid and the cyclic carbodiimide compound. More preferred is 0.02 to 0.1 parts by weight.

  The application amount of the cyclic carbodiimide compound is selected such that the carbodiimide group contained in the cyclic carbodiimide compound is 0.5 to 100 equivalents per equivalent of acidic group. If the amount is less than 0.5 equivalent, there may be no significance in applying carbodiimide. On the other hand, if it exceeds 100 equivalents, the characteristics of the substrate may be altered. From this viewpoint, on the above criteria, a range of preferably 0.6 to 100 equivalents, more preferably 0.65 to 70 equivalents, further preferably 0.7 to 50 equivalents, and particularly preferably 0.7 to 30 equivalents is selected. Is done.

<Method for producing polylactic acid-containing composite fiber>
The composite fiber of the present invention is required to be a composite of the polylactic acid composition described above and at least one thermoplastic resin composition. It does not specifically limit as this thermoplastic resin composition, What is necessary is just to change suitably according to a required function.

  Specific examples of the thermoplastic resin composition combined with the polylactic acid composition of the present invention include aromatic polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, nylon 6, nylon 66, nylon 610, nylon. 11 polyamide resin, acrylic resin such as polymethyl methacrylate, olefin resin such as polyethylene and polypropylene, polyvinyl alcohol resin, polyvinyl chloride resin, fluorine resin such as polytetrafluoroethylene, polyurethane resin, PPS Resins etc. are maintained as examples. As a result, various physical properties can be imparted. For example, if a composite fiber can be formed with polyethylene terephthalate, a fiber having a high bio raw material rate can be realized while improving the abrasion resistance of polylactic acid having a relatively low performance. In addition, fibers having functions such as heat resistance and flame retardancy and having a high bio raw material ratio that is environmentally friendly are possible.

  The thermoplastic resin composition may be a copolymer, a blend with an organic and / or inorganic substance, and a matting agent, a flame retardant, a heat resistance agent, a light resistance agent, and an ultraviolet absorber. Further, inorganic fine particles such as coloring pigments and organic compounds may be added.

  The method for combining the polylactic acid resin composition and the thermoplastic resin composition of the present invention is not particularly limited, and is a method of compounding at the time of fiber formation, such as melt compounding or solution compounding, or coating for applying a melt coating to a fiber once obtained Laws are exemplified.

  In addition, there is no particular limitation on the composite shape, and composite shapes such as core-sheath composite, sea-island composite, side-by-side, blend type can be adopted, for example, when it is desired to improve the wear resistance and flame retardancy of composite fiber The core-sheath composite type and the sea-island composite type are preferred, and when it is desired to provide a crimping function, the side-by-side type, the eccentric core-sheath type, the polylactic acid resin and the other thermoplastic resin are compatible, or one resin is finely If it is desired to disperse, a blend type may be employed.

  In particular, the core-sheath composite type, sea-island composite type, and blend type composite fiber, which can be expected to have an effect of improving wear resistance, can be further improved by using a resin having excellent wear resistance such as a polyamide-based resin. be able to. The composite component of the present invention may be composed of three or more components.

  The ratio of the resin to be combined is not particularly limited, but it is desirable that the bio raw material degree is higher as described above, and the ratio of the polylactic acid resin composition is preferably 20% by volume or more, more preferably 30% by volume. That's it.

(Step of melt spinning to obtain undrawn yarn (1))
The polylactic acid-containing composite fiber of the present invention is obtained by melting the above-mentioned polylactic acid composition and the thermoplastic resin composition with separate extruder-type or pressure melter-type melt extruders, and then combining the desired composite fiber with a gear pump. Both components are weighed so as to match the ratio, combined in a known spinneret for producing composite fibers, and ejected from a nozzle provided in the spinneret as monofilaments, multifilaments, etc., and spun.

  Thereafter, at a position of 5 to 200 mm below the spinneret, the spinning yarn is blown with air at 10 to 40 ° C. to be cooled and solidified, and then a spinning oil agent is applied for the purpose of reducing friction and converging, and spinning speed. It is taken up at 100 to 3000 m / min and wound on a bobbin using a winder, or the undrawn yarn obtained in a container such as a can in a state of tow of several hundred to several tens of thousands dtex is stored. The spinning speed is not particularly limited, but if it exceeds 3000 m / min, crystals due to orientation crystallization are generated in the undrawn yarn, and the strength after drawing tends to decrease. This is a preferred mode in many cases, and is selected in the range of 100 to 3000 m / min depending on the equipment, the desired fineness, and the high elongation properties. In particular, mass production machines for short fibers often take the process of bundling undrawn yarn tows of tens to thousands of filaments into hundreds to tens of thousands dtex and receiving them in containers such as buckets and cans. A spinning speed of 2000 m / min or less that can be stored in the container so as not to be entangled is preferably selected.

(Stretching process (2) that performs one-stage stretching or multistage stretching of two or more stages)
The unstretched yarn is wound around a bobbin once or stored in a container such as a can, and then supplied to a known stretcher for separate stretching. The stretching may be one-stage stretching or multi-stage stretching of two or more stages. The stretching temperature is preferably 20 to 150 ° C. from the viewpoint of process stability, and more preferably stretched at 50 to 100 ° C.

When stretching in a liquid bath, the medium used in the liquid bath is water, silicone oil, organic solvents such as ethylene glycol or acetone, inorganic salt solutions such as potassium chloride aqueous solution, supercritical carbon dioxide, etc. In view of contamination of the process and fibers, safety of the work surface, etc., water is most preferable. For the water bath drawing, a hot water bath or the like known as mass production equipment for polyester short fibers can be used. In the case of a water bath, the stretching temperature is 20 to 100 ° C.
The stretching ratio is 1.5 to 6.0 times, more preferably 2.5 to 4.5 times.

(Step of performing constant length heat treatment or relaxation heat treatment (3))
Subsequently, the drawn yarn is subjected to constant-length heat treatment or relaxation heat shrinkage. The constant length heat treatment is 110 to 200 ° C, preferably 120 to 190 ° C. When the constant length heat treatment temperature is less than 110 ° C., crystallization is insufficient and physical properties such as strength are insufficient. When the constant-length heat treatment temperature exceeds 200 ° C., it is not preferable because part of the heat treatment starts melting. The relaxation heat treatment is performed at 110 to 165 ° C, preferably 120 to 160 ° C. When the relaxation heat treatment temperature is less than 130 ° C., crystallization is similarly insufficient, and when it exceeds 165 ° C., a part of crystal melting caused by stretching starts, and heat shrinkage and fiber hardening start.

  The constant-length heat treatment can be performed by contacting the heated yarn with a heated medium or an electric heater with a constant tension applied to the drawn yarn, contact with a roller or contact heater, and superheated high-temperature steam ( There is a non-contact heating method using radiant heat such as a steam or hot air circulation chamber or an infrared heater.

  On the other hand, the relaxation heat treatment includes a method in which the drawn yarn is passed through a hot air circulation chamber, a suction drum through which hot air passes, a heating roller or a contact heater in an overfeed state without tension. As described above, the heating method for the drawn yarn in the constant length heat treatment or the relaxation heat treatment is preferably performed in a dry heat atmosphere or by contact with a dry heat heater.

  In the case of producing short fibers in the polylactic acid-containing composite fiber of the present invention, in addition to the method of drawing with long fibers, a step of cutting with a rotary cutter or the like to a predetermined fiber length according to the use, and further crimping are required. In this case, a step of imparting crimp with an indentation crimper or the like is added between the constant length heat treatment and relaxation heat treatment. At this time, in order to improve crimp imparting property, the fibers before crimping can be preheated with steam, an electric heater or the like.

<Stabilizer>
The polylactic acid composition used for the polylactic acid-containing composite fiber of the present invention can contain a stabilizer. As a stabilizer, what is used for the stabilizer of a normal thermoplastic resin can be used. For example, an antioxidant, a light stabilizer, etc. can be mentioned. By blending these agents, a molded product having excellent mechanical properties, moldability, heat resistance and durability can be obtained.

  Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, phosphite compounds, thioether compounds, and the like.

  Examples of hindered phenol compounds include n-octadecyl-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′-methyl-5 ′). -Tert-butyl-4'-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) -propionate, 1,6-hexanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionate], 1,4-butanediol-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -Propionate], 2,2'-methylene-bis (4-methyl-tert-butylphenol), triethylene glycol-bis 3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate], tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) propionate] methane, 3,9-bis [2- {3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} -1,1-dimethylethyl] 2,4,8,10-tetraoxaspiro ( 5,5) Undecane and the like can be mentioned.

  As a hindered amine compound, N, N′-bis-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionylhexamethylenediamine, N, N′-tetramethylene-bis [3- (3′-Methyl-5′-tert-butyl-4′-hydroxyphenyl) propionyl] diamine, N, N′-bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) -propionyl ] Hydrazine, N-salicyloyl-N'-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N'-bis [2- {3- (3,5-di -Tert-butyl-4-hydroxyphenyl) propionyloxy} ethyl] oxyamide and the like. Preferably, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate] and tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl) -4-hydroxyphenyl) propionate] methane and the like.

  As the phosphite compound, those in which at least one P—O bond is bonded to an aromatic group are preferable. Specifically, tris (2,6-di-tert-butylphenyl) phosphite, tetrakis ( 2,6-di-tert-butylphenyl) 4,4′-biphenylene phosphite, bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol di-phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, 1,1,3-tris (2-methyl-4-ditridecyl phosphite-5-tert-butylphenyl) butane, tris (mixed mono and di-no Butylphenyl) phosphite, tris (nonylphenyl) phosphite, 4,4'-isopropylidene-bis (phenyl - dialkyl phosphite), and the like.

  Among them, tris (2,6-di-tert-butylphenyl) phosphite, 2,2-methylenebis (4,6-di-tert-butylphenyl) octyl phosphite, bis (2,6-di-tert-butyl) -4-Methylphenyl) pentaerythritol-diphosphite, tetrakis (2,6-di-tert-butylphenyl) 4,4′-biphenylene phosphite and the like can be preferably used.

  Specific examples of thioether compounds include dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol-tetrakis (3-lauryl thiopropionate), Pentaerythritol-tetrakis (3-dodecylthiopropionate), pentaerythritol-tetrakis (3-octadecylthiopropionate), pentaerythritol tetrakis (3-myristylthiopropionate), pentaerythritol-tetrakis (3-stearylthio) Propionate) and the like.

  Specific examples of the light stabilizer include benzophenone compounds, benzotriazole compounds, aromatic benzoate compounds, oxalic acid anilide compounds, cyanoacrylate compounds, hindered amine compounds, and the like.

  Examples of the benzophenone compounds include benzophenone, 2,4-dihydroxybenzophenone, 2,2′-dihydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,2 ′. -Dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 5-chloro-2-hydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-methoxy -2 - carboxy benzophenone, 2-hydroxy-4- (2-hydroxy-3-methyl - acryloxy-isopropoxyphenyl) benzophenone.

  Examples of the benzotriazole compound include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3,5- Di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (3 ′, 5′-di-tert-butyl-4′-methyl-2′-hydroxyphenyl) benzotriazole, 2- (3,5- Di-tert-amyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (5-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (Α, α-Dimethylbenzyl) phenyl] benzotriazole, 2- [2′-hydroxy-3 ′, 5′-bis (α, α Dimethylbenzyl) phenyl] -2H- benzotriazole, 2- (4'-octoxy-2'-hydroxyphenyl) benzotriazole.

  Examples of the aromatic benzoate compounds include alkylphenyl salicylates such as p-tert-butylphenyl salicylate and p-octylphenyl salicylate.

  Examples of oxalic acid anilide compounds include 2-ethoxy-2′-ethyloxalic acid bisanilide, 2-ethoxy-5-tert-butyl-2′-ethyloxalic acid bisanilide, and 2-ethoxy-3′-. Examples include dodecyl oxalic acid bisanilide.

  Examples of the cyanoacrylate compound include ethyl-2-cyano-3,3'-diphenyl acrylate, 2-ethylhexyl-cyano-3,3'-diphenyl acrylate, and the like.

  Examples of hindered amine compounds include 4-acetoxy-2,2,6,6-tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6, 6-tetramethylpiperidine, 4- (phenylacetoxy) -2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2, 6,6-tetramethylpiperidine, 4-octadecyloxy-2,2,6,6-tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2 , 6,6-tetramethylpiperidine, 4-phenoxy-2,2,6,6-tetramethylpiperidine, 4- (ethylcarba Yloxy) -2,2,6,6-tetramethylpiperidine, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidine, 4- (phenylcarbamoyloxy) -2,2,6,6 -Tetramethylpiperidine, bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-4-piperidyl) oxalate, bis (2,2,6 , 6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethylpi-4-peridyl) adipate, bis (2,2,6,6-tetramethylpi-4-peridyl) terephthalate, 1,2-bis (2,2,6,6-tetramethylpi-4-peridylo) Cis) -ethane, α, α′-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyl) -Tolylene-2,4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) -hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl -4-piperidyl) -benzene-1,3,5-tricarboxylate, tris (2,2,6,6-tetramethyl-4-piperidyl) -benzene-1,3,4-tricarboxylate, 1- “2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} -2,2,6,6-tetramethylpiperidine, 1,2,3,4-butanetetracarboxylic acid And 1,2,2, , 6-Pentamethyl-4-piperidinol and β, β, β ′, β′-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro (5,5) undecane] dimethanol And the like. In the present invention, the stabilizer component may be used alone or in combination of two or more. As the stabilizer component, a hindered phenol compound and / or a benzotriazole compound are preferable. The content of the stabilizer is preferably 0.01 to 3 parts by weight, more preferably 0.03 to 2 parts by weight, per 100 parts by weight of polylactic acid.

<Antiwear agent>
In the present invention, a fatty acid bisamide and / or an alkyl-substituted monoamide can be contained in order to improve the abrasion resistance of the polylactic acid composition used for the polylactic acid-containing composite fiber.

  An aliphatic bisamide refers to a compound having two amide bonds in one molecule such as a saturated fatty acid bisamide, an unsaturated fatty acid bisamide, an aromatic fatty ginseng bisamide, such as methylene biscaprylic amide, methylene biscapric amide, Methylene bis lauric acid amide, methylene bis myristic acid amide, methylene bis palmitic acid amide, methylene bis stearic acid amide, methylene bis isostearic acid amide, methylene bis behenic acid amide, methylene bis oleic acid amide, methylene bis erucic acid amide, Ethylene biscaprylic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bismyristic acid amide, ethylene bispalmitic acid amide, ethylene bisstearic acid amide, ethylene bisisostearate Acid amide, ethylene bis behenic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, butylene bis oleic acid amide, butylene bis erucic acid amide, Hexamethylene bis stearic acid amide, hexamethylene bis behenic acid amide, hexamethylene bis oleic acid amide, hexamethylene bis erucic acid amide, m-xylylene bis stearic acid amide, m-xylylene bis-12-hydroxy stearic acid amide, p-xylylene bis-stearic acid amide, p-phenylene bis-stearic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N'-di Stearyl terephthalic acid amide, methylene bis-hydroxystearic acid amide, ethylenebis-hydroxystearic acid amide, butylene-bis-hydroxystearic acid amide, hexamethylene bis hydroxystearic acid amide.

  In addition, the alkyl-substituted monoamide referred to in the present invention refers to a compound having a structure in which amide hydrogen such as saturated fatty acid monoamide or unsaturated fatty acid monoamide is substituted with an alkyl group, such as N-lauryl lauric acid amide, N-par. Mitylpalmitic acid amide, N-stearyl stearic acid amide, N-hebenyl hebenic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid Examples include acid amides. In the alkyl group, a substituent such as a hydroxyl group may be introduced into the structure. For example, methylose stearamide, N-stearyl-12-hydroxystearic amide, N-oleyl-12-hydroxystearin Acid amides and the like are also included in the alkyl-substituted fatty acid amides of the present invention.

  These compounds are less reactive with amides than ordinary fatty acid monoamides, and hardly react with polylactic acid during melt molding. In addition, since many of them have a high molecular weight, they generally have good heat resistance and are difficult to sublimate. In particular, fatty acid bisamides can be used as a more preferred antiwear agent because they are less reactive with polylactic acid due to their lower reactivity with amides, and because they have a high molecular weight, they have good heat resistance and are not easily sublimated. Examples of such antiwear agents include ethylene bis stearamide, ethylene bisisostearic acid amide, ethylene bis behenic acid amide, butylene bis stearic acid amide, butylene bis behenic acid amide, hexamethylene bis behenine. Acid amide and m-xylylene bis-stearic acid amide are preferable.

  In the present invention, the content of fatty acid bisamide and / or alkyl-substituted monoamide (hereinafter abbreviated as “fatty acid amide”) with respect to the entire short fibers is preferably 0.1 to 1.5 wt%. More preferably, it is 0.5 to 1.0 wt%. When the content of the fatty acid amide is 0.1 wt% or less, a sufficient effect for the purpose does not appear, and when the content is 1.5 wt% or more, the slipping property of the short fiber is improved, but the effect is too great, so It leads to deterioration in operability due to intertwining and deterioration in quality such as deterioration in crimp uniformity. The fatty acid amide may be a single component, or a plurality of components may be mixed.

<Crystallization accelerator>
The polylactic acid composition of the present invention can contain an organic or inorganic crystallization accelerator. By containing the crystallization accelerator, a molded product having excellent mechanical properties, heat resistance, and moldability can be obtained.
That is, by applying the crystallization accelerator, moldability and crystallinity are improved, and a molded product that is sufficiently crystallized even in normal injection molding and excellent in heat resistance and moist heat resistance can be obtained. In addition, the manufacturing time for manufacturing the molded product can be greatly shortened, and the economic effect is great.

As the crystallization accelerator used in the present invention, those generally used as crystallization nucleating agents for crystalline resins can be used, and both inorganic crystallization nucleating agents and organic crystallization nucleating agents are used. be able to.
As inorganic crystallization nucleating agents, talc, kaolin, silica, synthetic mica, clay, zeolite, graphite, carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium carbonate, calcium sulfate, barium sulfate, calcium sulfide, boron nitride Montmorillonite, neodymium oxide, aluminum oxide, phenylphosphonate metal salt and the like. These inorganic crystallization nucleating agents are treated with various dispersing aids in order to enhance the dispersibility in the composition and the effect thereof, and are in a highly dispersed state with a primary particle size of about 0.01 to 0.5 μm. Are preferred.

  Organic crystallization nucleating agents include calcium benzoate, sodium benzoate, lithium benzoate, potassium benzoate, magnesium benzoate, barium benzoate, calcium oxalate, disodium terephthalate, dilithium terephthalate, dipotassium terephthalate, Sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, barium myristate, sodium octacolate, calcium octacolate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate , Barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, potassium salicylate, salicy Organic carboxylic acid metal salts such as zinc acid, aluminum dibenzoate, β-naphthoic acid sodium, β-naphthoic acid potassium, sodium cyclohexanecarboxylic acid and the like, and organic sulfonic acid metal salts such as sodium p-toluenesulfonate and sodium sulfoisophthalate. Can be mentioned.

  Also, organic carboxylic acid amides such as stearic acid amide, ethylenebislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, trimesic acid tris (tert-butylamide), low density polyethylene, high density polyethylene, polyiso Propylene, polybutene, poly-4-methylpentene, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, high melting point polylactic acid, sodium salt of ethylene-acrylic acid copolymer, sodium of styrene-maleic anhydride copolymer Examples thereof include salts (so-called ionomers), benzylidene sorbitol and derivatives thereof such as dibenzylidene sorbitol.

Among these, at least one selected from talc and organic carboxylic acid metal salts is preferably used. Only one type of crystallization accelerator may be used in the present invention, or two or more types may be used in combination.
The content of the crystallization accelerator is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight per 100 parts by weight of polylactic acid.

<Antistatic agent>
The polylactic acid composition used for the polylactic acid-containing composite fiber of the present invention can contain an antistatic agent. Examples of the antistatic agent include quaternary ammonium salt compounds such as (β-lauramidopropionyl) trimethylammonium sulfate and sodium dodecylbenzenesulfonate, sulfonate compounds, and alkyl phosphate compounds.
In the present invention, the antistatic agent may be used alone or in combination of two or more. The content of the antistatic agent is preferably 0.05 to 5 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of polylactic acid.

<Plasticizer>
The polylactic acid composition used for the polylactic acid-containing composite fiber of the present invention can contain a plasticizer. As the plasticizer, generally known plasticizers can be used. Examples include polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, phosphate ester plasticizers, polyalkylene glycol plasticizers, and epoxy plasticizers.

  As a polyester plasticizer, acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid and ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, Examples thereof include polyesters composed of diol components such as 1,6-hexanediol and diethylene glycol, and polyesters composed of hydroxycarboxylic acids such as polycaprolactone. These polyesters may be end-capped with a monofunctional carboxylic acid or a monofunctional alcohol.

  Examples of the glycerol plasticizer include glycerol monostearate, glycerol distearate, glycerol monoacetomonolaurate, glycerol monoacetomonostearate, glycerol diacetomonooleate, and glycerol monoacetomonomontanate.

  Polyvalent carboxylic acid plasticizers include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, trimellitic acid tributyl, trimellitic acid trioctyl, Trimellitic acid esters such as trihexyl meritate, isodecyl adipate, adipic acid esters such as adipate-n-decyl-n-octyl, citrate esters such as tributyl acetylcitrate, and bis (2-ethylhexyl) azelate Examples include sebacic acid esters such as azelaic acid ester, dibutyl sebacate, and bis (2-ethylhexyl) sebacate.

  Examples of the phosphate ester plasticizer include tributyl phosphate, tris phosphate (2-ethylhexyl), trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, diphenyl-2-ethylhexyl phosphate, and the like.

  Polyalkylene glycol plasticizers such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, poly (ethylene oxide-propylene oxide) block and / or random copolymers, ethylene oxide addition polymers of bisphenols, tetrahydrofuran addition polymers of bisphenols, etc. And end-capping compounds such as a terminal epoxy-modified compound, a terminal ester-modified compound, and a terminal ether-modified compound.

  Examples of the epoxy plasticizer include an epoxy triglyceride composed of alkyl epoxy stearate and soybean oil, and an epoxy resin using bisphenol A and epichlorohydrin as raw materials.

  Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol-bis (2-ethylbutyrate), and fatty acids such as stearamide. Examples thereof include fatty acid esters such as amide and butyl oleate, oxyacid esters such as methyl acetylricinoleate and butyl acetylricinoleate, pentaerythritol, various sorbitols, polyacrylic acid esters, silicone oils, and paraffins.

  As the plasticizer, at least one selected from polyester-type plasticizers and polyalkylene-type plasticizers can be preferably used, and only one type may be used, or two or more types may be used in combination.

  The content of the plasticizer is preferably 0.01 to 30 parts by weight, more preferably 0.05 to 20 parts by weight, and still more preferably 0.1 to 10 parts by weight per 100 parts by weight of polylactic acid. In the present invention, each of the crystallization nucleating agent and the plasticizer may be used alone, or more preferably used in combination.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these specific examples. The method for measuring the characteristics used in this example is as follows.

(1) Hydrolysis resistance:
Hydrolysis resistance is determined to be good when the carboxyl group terminal amount of the composition is 0 equivalent / ton, and is determined to be acceptable when it is 10 equivalent / ton or less, and exceeds 10 equivalent / ton. No. The terminal amount of the carboxyl group was determined by dissolving a weighed sample in o-cresol adjusted to a water content of 5%, adding an appropriate amount of dichloromethane to this solution, and titrating with 0.02 N potassium hydroxide methanol solution. .

(2) Melting point, crystallization point:
A TA-2920 differential scanning calorimeter DSC manufactured by TA Instruments was used. In the measurement, 10 mg of a sample was heated from room temperature to 260 ° C. at a heating rate of 10 ° C./min in a nitrogen atmosphere, and the peak top temperatures of the crystal melting endothermic peak and the crystallization exothermic peak were defined as the melting point and the crystallization point, respectively. .

(3) Strength:
Using “Tensilon” (trade name) manufactured by Orientic Corporation, ten target single yarns (filaments) are randomly extracted from the fiber structure to be measured, the yarn sample length is 50 mm (length between chucks), and the elongation speed is 500 mm. The strain-stress curve was measured under the conditions of an atmospheric temperature of 20 ° C. and a relative humidity of 65% under the conditions of / min, and after obtaining the strength (cN / piece) from the stress and elongation at the breaking point, the strength was divided by the fineness. The fiber strength (cN / dtex).

(4) Quality of work environment:
Judgment was made based on whether the working environment was deteriorated by the isocyanate odor during the production of the resin composition. When it did not deteriorate, it was evaluated as good.

(5) Isocyanate odor generated:
When the obtained polylactic acid-containing composite fiber was melted at 300 ° C. for 5 minutes, it was determined by sensory evaluation whether the measurer felt an isocyanate odor. When the isocyanate odor was not felt, it was judged to be acceptable.

In this example, the following agents were produced and used as the cyclic carbodiimide compound.
[Production Example 1] Synthesis of cyclic carbodiimide compound CC1 (MW = 252):
Reaction in which 200 ml of o-nitrophenol (0.11 mol), 1,2-dibromoethane (0.05 mol), potassium carbonate (0.33 mol), and N, N-dimethylformamide (DMF) were installed with a stirrer and a heating device The apparatus was charged in an N ₂ atmosphere and reacted at 130 ° C. for 12 hours. After that, DMF was removed under reduced pressure, and the resulting solid was dissolved in 200 ml of dichloromethane and separated three times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and dichloromethane was removed under reduced pressure to obtain an intermediate product A (nitro form).

  Next, intermediate product A (0.1 mol), 5% palladium carbon (Pd / C) (1 g), and 200 ml of ethanol / dichloromethane (70/30) were charged into a reactor equipped with a stirrer, and 5 hydrogen substitution was performed. The reaction was performed in a state where hydrogen was constantly supplied at 25 ° C., and the reaction was terminated when there was no decrease in hydrogen. When Pd / C was recovered and the mixed solvent was removed, an intermediate product B (amine body) was obtained.

Next, triphenylphosphine dibromide (0.11 mol) and 150 ml of 1,2-dichloroethane were charged and stirred in a reactor equipped with a stirring device, a heating device, and a dropping funnel in an N ₂ atmosphere. A solution prepared by dissolving intermediate product B (0.05 mol) and triethylamine (0.25 mol) in 50 ml of 1,2-dichloroethane was gradually added dropwise thereto at 25 ° C. After completion of dropping, the reaction was carried out at 70 ° C. for 5 hours. Thereafter, the reaction solution was filtered, and the filtrate was separated 5 times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and 1,2-dichloroethane was removed under reduced pressure to obtain an intermediate product C (triphenylphosphine compound).

Next, in a reactor equipped with a stirrer and a dropping funnel, di-tertbutyl dicarbonate (0.11 mol), N, N-dimethyl-4-aminopyridine (0.055 mol), dichloromethane 150 ml under N ₂ atmosphere. Were charged and stirred. Thereto, 100 ml of dichloromethane in which the intermediate product C (0.05 mol) was dissolved was slowly added dropwise at 25 ° C. After dropping, the reaction was allowed to proceed for 12 hours.
Then, CC1 shown by the following structural formula was obtained by refine | purifying the solid substance obtained by removing dichloromethane. The structure of CC1 was confirmed by NMR and IR.

[Production Example 2] Synthesis of cyclic carbodiimide compound CC2 (MW = 516):
o- nitrophenol (0.11 mol) and pentaerythrityl tetra bromide (0.025 mol), potassium carbonate (0.33mol), _N, N ₂ N- dimethylformamide 200ml in reactor installed with a stirrer and a heating device After charging in an atmosphere and reacting at 130 ° C. for 12 hours, DMF was removed under reduced pressure, and the resulting solid was dissolved in 200 ml of dichloromethane and separated three times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and dichloromethane was removed under reduced pressure to obtain an intermediate product D (nitro form).

  Next, intermediate product D (0.1 mol), 5% palladium carbon (Pd / C) (2 g), and 400 ml of ethanol / dichloromethane (70/30) were charged into a reactor equipped with a stirrer, and 5 hydrogen substitution was performed. The reaction was performed in a state where hydrogen was constantly supplied at 25 ° C., and the reaction was terminated when there was no decrease in hydrogen. Pd / C was recovered, and the mixed solvent was removed to obtain an intermediate product E (amine body).

Next, triphenylphosphine dibromide (0.11 mol) and 150 ml of 1,2-dichloroethane were charged and stirred in a reactor equipped with a stirrer, a heating device, and a dropping funnel in an N ₂ atmosphere. A solution prepared by dissolving the intermediate product E (0.025 mol) and triethylamine (0.25 mol) in 50 ml of 1,2-dichloroethane was gradually added dropwise thereto at 25 ° C. After completion of dropping, the reaction was carried out at 70 ° C. for 5 hours.
Thereafter, the reaction solution was filtered, and the filtrate was separated 5 times with 100 ml of water. The organic layer was dehydrated with 5 g of sodium sulfate, and 1,2-dichloroethane was removed under reduced pressure to obtain an intermediate product F (triphenylphosphine compound).

Next, in a reactor equipped with a stirrer and a dropping funnel, di-tert-butyl dicarbonate (0.11 mol), N, N-dimethyl-4-aminopyridine (0.055 mol), dichloromethane under N ₂ atmosphere. 150 ml is charged and stirred. Thereto, 100 ml of dichloromethane in which the intermediate product F (0.025 mol) was dissolved was slowly added dropwise at 25 ° C. After dropping, the reaction was allowed to proceed for 12 hours.
Then, CC2 shown by the following structural formula was obtained by refine | purifying the solid substance obtained by removing dichloromethane. The structure of CC2 was confirmed by NMR and IR.

[Production Example 3] (Production of poly L-lactic acid)
To 100 parts by weight of L-lactide (manufactured by Musashino Chemical Laboratory, Inc., 100% optical purity), 0.005 part by weight of octyltinate was added, and the reaction was carried out at 180 ° C. in a reactor equipped with a stirring blade in a nitrogen atmosphere. After reacting for 2 hours, phosphoric acid equivalent to 1.2 times the amount of tin octylate was added, and then the remaining lactide was removed at 13.3 kPa to obtain chips to obtain poly L-lactic acid.
The obtained L-lactic acid had a weight average molecular weight of 150,000, a glass transition point (Tg) of 63 ° C., and a melting point of 180 ° C.

[Production Example 4] (Production of poly-D-lactic acid)
To 100 parts by weight of D-lactide (manufactured by Musashino Chemical Laboratory, Inc., 100% optical purity), 0.005 part by weight of tin octylate was added, and the reactor was stirred at 180 ° C. with a stirring blade in a nitrogen atmosphere. After reacting for 2 hours, phosphoric acid equivalent to 1.2 times the amount of tin octylate was added, and then the remaining lactide was removed at 13.3 kPa to obtain chips to obtain poly-D-lactic acid.
The obtained poly-D-lactic acid had a weight average molecular weight of 150,000, a glass transition point (Tg) of 63 ° C., and a melting point of 180 ° C.

[Production Example 5] (Production of stereocomplex polylactic acid resin)
50 parts by weight of each of the poly L-lactic acid obtained in Production Example 3 and the poly D-lactic acid of Production Example 4 and a phosphate ester metal salt (2,2-methylenebis (4,6-di-tert-butylphenol) phosphate) Sodium complex, average particle size 5 μm, “ADEKA STAB” NA-11, manufactured by ADEKA Corporation, 0.1 part by weight is melt-kneaded at 230 ° C., strands are taken in a water tank, chips are formed with a chip cutter, and stereocomplex polylactic acid chips Got. The obtained stereocomplex polylactic acid resin had an Mw of 135,000, a melting point (Tm) of 217 ° C., and a stereocomplex crystallinity of 100%.

[Example 1] Production of side-by-side type composite fiber 1:
After drying the poly L-lactic acid chip and the cyclic carbodiimide compound (CC1) obtained by the operation of Production Example 3, the pellets obtained by melt blending to a weight ratio of 99: 1 are biaxially melted. It was supplied to an extruder (using a vent) and discharged at 325 g / min from one side of a side-by-side die having 260 holes. On the other hand, polybutylene terephthalate (Wintech Polymer Co., Ltd. “Duranex” TRE-DM2) is supplied from a loss-in-weight type weight feeder to a twin-screw melt extruder (using a vent), and 325 g / min from the other side-by-side die. Was discharged.
Thereafter, the undrawn yarn was wound up at a speed of 800 m / min while being cooled and solidified by blowing air at 25 ° C. at a position 40 mm below the base. The unstretched yarn is bundled to form a 500,000 dtex tow (hereinafter, sometimes abbreviated as unstretched tow), stretched 3.47 times in 60 ° C. warm water, and subsequently 1.90 in 90 ° C. warm water. The film was stretched 05 times to obtain a total draw ratio of 3.64 times. Thereafter, six metal rollers heated with 0.85 MPa water vapor were passed through, and after the passage, a constant length heat treatment (1.0 times) was performed at a tow temperature of 185 ° C. to give an oil agent composed of stearyl phosphate potassium salt. Thereafter, tow heated to 80 ° C. with water vapor was supplied to the indentation type crimper, 14 pieces / 25 mm of crimp were applied, and then passed through a circulating hot air at 60 ° C. for 50 minutes for relaxation heat treatment. Then, it cut with the rotary cutter and obtained the short fiber of 8.95 dtex and 64 mm. The obtained fiber had a dry strength of 2.56 cN / dtex.
Generation of isocyanate odor was not felt during melt-kneading and spinning. Moreover, when the obtained composite fiber was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
In addition, the amount of carboxyl terminal groups of the polylactic acid resin pellets obtained by melt blending the cyclic carbodiimide compound (CC1) is 1 equivalent / ton, and in the discharged yarn obtained when spinning only the polylactic acid side during the composite spinning. The amount of end group of ruboxyl was 2 equivalent / ton.

[Example 2] Production of side-by-side type composite fiber 2:
It implemented like Example 1 except having used the stereocomplex polylactic acid chip and cyclic carbodiimide compound (CC2) which were obtained by operation of manufacture example 5, and obtained a short fiber of 8.95 dtex and 64 mm. The obtained fiber had a dry strength of 2.60 cN / dtex.
Generation of isocyanate odor was not felt during melt-kneading and spinning. Moreover, when the obtained composite fiber was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
In addition, the amount of carboxyl terminal groups of the polylactic acid resin pellet obtained by melt blending the cyclic carbodiimide compound is 1 equivalent / ton, and the ruxyl terminal group in the release yarn obtained when spinning only the polylactic acid side during the composite spinning. The amount was 1 equivalent / ton.

[Example 3] Production of core-sheath type composite fiber:
In the production of the side-by-side type composite fiber of Example 2, the pack structure and the base were changed to the core-sheath type, and the stereocomplex polylactic acid chip and the cyclic carbodiimide compound (CC2) obtained by the operation of Production Example 5 were in weight ratio. Pellets obtained by melt blending to 99: 1 were discharged at 325 g / min from the sheath side of the 260-hole discharge hole. On the other hand, polybutylene terephthalate (Wintech Polymer Co., Ltd. “DURANEX” TRE-DM2) is supplied from a loss-in-weight type weight feeder to a twin-screw melt extruder (using a vent), and from the core side of the aforementioned core-sheath die. It was discharged at 325 g / min.
Thereafter, the undrawn yarn was wound up at a speed of 800 m / min while being cooled and solidified by blowing air at 25 ° C. at a position 40 mm below the base. The unstretched yarn is bundled to form a 500,000 dtex tow (hereinafter, sometimes abbreviated as unstretched tow), stretched 3.5 times in warm water at 60 ° C., and then 1. The film was stretched 05 times to obtain a total draw ratio of 3.25 times. Thereafter, six metal rollers heated with 0.85 MPa water vapor were passed through, and after the passage, a constant length heat treatment (1.0 times) was performed at a tow temperature of 185 ° C. to give an oil agent composed of stearyl phosphate potassium salt. Thereafter, tow heated to 80 ° C. with water vapor was supplied to the indentation type crimper, 14 pieces / 25 mm of crimp were applied, and then passed through a circulating hot air at 60 ° C. for 50 minutes for relaxation heat treatment. Then, it cut with the rotary cutter and obtained the 9.0 decitex and the short fiber of 64 mm. The obtained fiber had a dry strength of 2.50 cN / dtex.
Generation of isocyanate odor was not felt during melt-kneading and spinning. Moreover, when the obtained composite fiber was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was acceptable.
In addition, the amount of carboxyl terminal groups of the polylactic acid resin pellet obtained by melt blending the cyclic carbodiimide compound (CC1) is 1 equivalent / ton, and in the discharged yarn obtained by spinning only the polylactic acid side at the time of composite spinning. The amount of endoxyl group was 2 equivalent / ton.

[Comparative Example 1]
In Example 1, it replaced with cyclic carbodiimide (CC1), and performed the same operation except having used the linear polycarbodiimide compound [The Nisshinbo Chemical Co., Ltd. product; "Carbodilite" HMV-8CA].
The amount of carboxyl terminal groups of the polylactic acid resin pellet obtained by melt blending the polylactic acid composition and the cyclic carbodiimide compound (CC1) was 2 equivalent / ton, and was obtained when spinning only the polylactic acid side during the composite spinning. The amount of carboxyl end groups in the discharged yarn was 3 equivalent / ton, but the generation of an isocyanate odor was felt particularly during spinning. Moreover, when the obtained side-by-side type composite yarn was melted at 300 ° C. for 5 minutes, the isocyanate odor evaluation was not acceptable.

[Comparative Example 2]
In Example 1, the same operation was performed except that the cyclic carbodiimide (CC1) was not used. Generation of isocyanate odor was not felt during melt-kneading and spinning. Further, when the melt was melted at 300 ° C. for 5 minutes, the evaluation of the isocyanate odor was acceptable, but the amount of carboxyl end groups in the discharged yarn obtained when spinning only the polylactic acid side was 39 equivalents / It was ton and was inferior to hydrolyzability.

  According to the present invention, it is possible to provide a polylactic acid-containing composite fiber that has improved hydrolysis resistance and does not generate a free isocyanate compound.

Claims (13)

  A polylactic acid-containing composite fiber comprising a polylactic acid composition containing a polylactic acid and a compound (C component) containing a cyclic structure in which one carbodiimide group and the first nitrogen and the second nitrogen are bonded by a bonding group .   The polylactic acid-containing composite fiber according to claim 1, wherein the number of atoms forming the cyclic structure of the C component is 8 to 50. The polylactic acid-containing composite fiber according to claim 1 or 2, wherein the cyclic structure of component C is represented by the following formula (1).

(In the formula, Q is a divalent to tetravalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom.) The polylactic acid-containing composite fiber according to claim 3, wherein Q is a divalent to tetravalent linking group represented by the following formula (1-1), (1-2) or (1-3).

(In the formula, Ar ¹ and Ar ² are each independently an aromatic group having 2 to 4 carbon atoms and 5 to 15 carbon atoms. R ¹ and R ² are each independently 1 to 2 carbon atoms having 1 to 4 carbon atoms. 20 aliphatic groups, 2 to 4 valent alicyclic groups having 3 to 20 carbon atoms, or combinations thereof, or these aliphatic groups, alicyclic groups and 2 to 4 valent aromatic carbon atoms having 5 to 15 carbon atoms X ¹ and X ² are each independently a divalent to tetravalent aliphatic group having 1 to 20 carbon atoms, a divalent to tetravalent carbon atom having 3 to 20 alicyclic groups, 2 to 4 A valent aromatic group having 5 to 15 carbon atoms, or a combination thereof, s is an integer of 0 to 10. k is an integer of 0 to 10. When s or k is 2 or more, X ¹ or X ² as a repeating unit may be different from other X ¹ or X ^2. X ³ is a divalent to tetravalent carbon number. An aliphatic group having 1 to 20 carbon atoms, an alicyclic group having 2 to 4 carbon atoms having 3 to 20 carbon atoms, an aromatic group having 2 to 4 carbon atoms having 5 to 15 carbon atoms, or a combination thereof, provided that Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ may contain a hetero atom, and when Q is a divalent linking group, Ar ¹ , Ar ² , R 3 ¹ , R ² , X ¹ , X ² and X ³ are all divalent groups, and when Q is a trivalent linking group, Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ^{One of 2} and X ³ is a trivalent group, and when Q is a tetravalent linking group, one of Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² and X ³ One of them is a tetravalent group or two are trivalent groups.) The polylactic acid-containing composite fiber according to claim 3, wherein the compound containing a cyclic structure of component C is represented by the following formula (2).

(In the formula, Qa is a divalent linking group that is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom.) The polylactic acid-containing composite fiber according to claim 5, wherein Qa is a divalent linking group represented by the following formula (2-1), (2-2), or (2-3).

(In the formula, Ar _a ¹ , Ar _a ² , R _a ¹ , R _a ² , X _a ¹ , X _a ² , X _a ³ , s and k are represented by the formulas (1-1) to (1-3), respectively. ^{Ar 1, Ar 2, R 1} , R 2, X 1, is the same as ^{X 2,} X ^3, s and k in.) The polylactic acid-containing composite fiber according to claim 3, wherein the compound containing a cyclic structure of component C is represented by the following formula (3).

(Wherein Q _b is a trivalent linking group which is an aliphatic group, an alicyclic group, an aromatic group, or a combination thereof, and may contain a hetero atom. Y represents a cyclic structure. It is a carrier to be supported.) Q _b is represented by the following formula (3-1), (3-2) or polylactic acid-containing composite fibers according to claim 7 is a trivalent linking group represented by (3-3).

(In the formula, Ar _b ¹ , Ar _b ² , R _b ¹ , R _b ² , X _b ¹ , X _b ² , X _b ³ , s and k are represented by the formulas (1-1) to (1-3), respectively. Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s, and k, with one of these being a trivalent group.)   The polylactic acid-containing composite fiber according to claim 7 or 8, wherein Y is a single bond, a double bond, an atom, an atomic group or a polymer. The polylactic acid-containing composite fiber according to claim 3, wherein the compound containing a C component cyclic structure is represented by the following formula (4).

(Wherein Q _c is a tetravalent linking group that is an aliphatic group, an aromatic group, an alicyclic group, or a combination thereof, and may have a hetero atom. Z ¹ and Z ² are A carrier carrying a ring structure.) 11. The polylactic acid-containing composite fiber according to claim 10, wherein Q _c is a tetravalent linking group represented by the following formula (4-1), (4-2), or (4-3).

(In the formula, Ar _c ¹ , Ar _c ² , R _c ¹ , R _c ² , X _c ¹ , X _c ² , X _c ³ , s and k are respectively represented by formulas (1-1) to (1-3) Are the same as Ar ¹ , Ar ² , R ¹ , R ² , X ¹ , X ² , X ³ , s and k, provided that one of them is a tetravalent group or two are 3 Valent group.) The polylactic acid-containing composite fiber according to claim 11, wherein Z ¹ and Z ² are each independently a single bond, a double bond, an atom, an atomic group or a polymer.   Content of C component is 0.001-10 weight part per 100 weight part polylactic acid, The polylactic acid containing composite fiber in any one of Claims 1-12.